Free calling on your smartphone isn't too difficult to come by. In many cases, all you need is the right app to route your calls over Wi-Fi instead of over your carrier's network. This week, we want to know which apps you think are the best for the job.

Whether you're roaming but still want to use your phone, or you just don't like to carry minutes on your phone but still use it for the ocassional call, the right VoIP app can make all the difference and save you a good bit of money. Sure, minutes aren't exactly expensive, but contracts can be—-some pre-paid carriers even let you install their VoIP app and use their network without leaving your current carrier for data. Which ones do you think are the best? Sound off below.

The call for contenders is closed! To see which of your nominees got enough support to make it to the top five, head over to our hive five feature, the five best mobile VoIP apps, to read more!

Follow this format for your vote, including the bold print. If you don't, it won't be counted:

A LOGO OR SCREENSHOT OF THE BEST MOBILE VOIP APP

Vote: [BEST MOBILE VOIP APP]

Why: Why is this app the one you think is the best? Maybe it works on all kinds of devices, or their charges are low (or it's free), or the company behind it is really cool. Make your case! Try to keep it to a single paragraph, maybe two.

Don't duplicate nominations! Instead, if someone's nominated your pick, star (recommend) it to give it a boost, and reply with your story instead.